The process is really simple and you can fully customise your soap from start to finish. Start with your soap base - there are a whole range to choose from. To give myself a few future options, I opted for a transparent base. Cut the base into squares of around 3cm [I found 3 of these filled one of my moulds, but the mould should let you know the water it can contain to help guide.

Transfer into a microwaveable jug and heat in 20 second bursts until melted:

Mix thoroughly and add any scent [or colouring] before filling your mould. I filled mine half way, before adding my 'scent' - I wanted this soap to have the same fresh scent and properties as the scrub DIY I posted a few weeks ago, so used this to fill my moulds. The transparent base would show the scrub floating [in theory!]:

Leave to sink and spread out, before topping the mould up with the remainder of your soap base to cover.

Leave the soap to set [this takes only around 15 minutes - quicker if you pop in the fridge] before removing easily from the moulds [make sure silicon is used]:

...and your soap is ready to be used. I think this is the start of a new obsession.